Continuously variable transmission

ABSTRACT

The present invention provides a mechanical continuously variable transmission in which the power roller is in “line contact” with the counter roller instead of conventional “pinpoint contact”. By utilizing line contact of the power roller and the counter roller, the pressure force between the metal components of a mechanical continuously variable transmission can be reduced. In addition, the line contact also reduces extra energy for maintaining the operation thereof. The configuration of the roll surface of the power roller, which is rotated by a rotation axle connected to an input axle, is formed into a partial configuration of a sphere. A plurality of counter rollers, which are in line contact with the power roller having said roll surface, are arranged in a circle by a disk. Each counter roller is formed with a concave roll surface corresponding to the partial configuration of the sphere on the surface thereof. The counter rollers are driven to rotate by the rotation of the power roller in contact therewith. Each counter roller is assembled rotatably on the same periphery of the disk connected to an output axle so that the concave roll surfaces neighboring to each other roughly continue into a toric shape. A rotation axle of the power roller is adapted so as to be continuously inclined with respect to the disk.

TECHNICAL FIELD

[0001] The present invention relates to a continuously variabletransmission that continuously transmits rotation and force (rotatingtorque) from input axle side to output axle side. In particular, theinvention relates to a continuously variable transmission that shifts inany forward/reverse rotation direction from a state of idling (neutral)in a continuously variable manner.

BACKGROUND ART

[0002] The use of fluid transmissions, in which a fluid is used, andmechanical transmissions, in which a planetary gear set or the like isused, to transfer the rotating torque generated by an engine of, forexample, an automobile, to the output axle at the wheel-side is wellknown. The mechanical transmissions can be broadly classified into twotypes. The first type uses a gear set and thereby gradually transmitsthe number of revolutions. The second type continuously transmits thenumber of revolutions.

[0003] The mechanical continuously variable transmission is classifiedin IPC F16H (transmission apparatus) 15/00 “transmission apparatus fortransmitting or reversing rotation having variable gear ratio by meansof friction between rotational members,” which also includes mechanicalcontinuously variable transmissions using the “friction.” Needless tosay, since the IPC F16H 15/00 classification is further minutelyclassified, it is understood that a variety of such mechanicalcontinuously variable transmissions using the friction have beenproposed.

[0004] Recent developments in mechanical continuously variabletransmissions have focused on toroidal Continuously VariableTransmissions (CVT), which are a type of a traction drive. The toroidalCVT was first proposed by Charies W. Hunt in U.S Pat. No. 197,472, whichhas the following basic characteristics. As shown in FIG. 32, a wheel E(hereinafter also referred to as power roller) that slides on disks Band D, which face each other and the inside surface of these disks isformed into a toroidal, i.e., doughnut-like shape, is disposed and bychanging the angle of the wheel E, the sliding contact radius of thewheel E can be changed relative to the disk B and disk D sides. Thus,when the rotating torque of the disk B is transmitted to the disk D, thenumber of revolutions is changed between the disks B and D.

[0005] As described above, the toroidal CVT according to the Hunt patenthas a toric (i.e. a toroidal shape, like a doughnut) as the entireconfiguration of the inner surface of the disks B and D. Hence,mechanical continuously variable transmissions that have a configurationlike that of the Hunt patent, have been called as toroidal CVTs.

[0006] The toroidal CVT according to the Hunt patent, having the basicstructure as shown in FIG. 32, is very simple and would have beensuitable in a wide variety of industrial applications. There was someexperimentation in the application of toroidal CVTs in the 1920s withthe emergence of automobiles and various trial products and salesthereof also were made. However, for various reasons, widespreadadoption of the toroidal CVT did not occur.

[0007] Since then, a variety of improvements to toroidal CVTs have beenmade. The configuration of the recent toroidal CVTs is largelyclassified into “full-toroidal” shown in FIG. 33 and “half-toroidal”shown in FIG. 34.

[0008] The characteristics of the full-toroidal CVT are basically thesame as the Hunt patent. As shown in FIG. 33, the center (the center ofthe straight line connecting the contact points O and O″ between theinput and output disks) of the power roller (in FIG. 32, equivalent tothe wheel E) goes through the center of a toroidal cavity formed by theinner surfaces of the disks. In this arrangement, because the pressurebetween the disks applied to transmit power between the input and outputdisks does not act on the support axle for relatively inclining thepower rollers, the angle of the power roller can be changed smoothly.From an alternative perspective, because the two tangent lines drawnfrom each contact points 0 and 0′ are parallel to each other, a largespin arises at the respective contact points.

[0009] On the other hand, in a half-toroidal CVT shown in FIG. 34, thetwo tangent lines from each of the contact points O and O′are notparallel to each other but have an intersection point E. When theintersection point E is on the rotation axle I, the spin at each contactpoint O, O′ is eliminated, resulting in an effective CVT.

[0010] In any case, in a toroidal CVT, high pressure is exerted on themetal components in order to keep the components pressed against eachother when they come into contact with each other at the shaded portionsin FIG. 35 (TANAKA Hirohisa, “Toroidal CVT” (in Japanese), published inJuly 2000 by Corona Publishing). When the metals come into contact witheach other at such small contact portions, as shown, friction heat isinevitably generated.

[0011] If there is no means to dissipate the friction heat, the metalcomponents will eventually seize up on each other. Thus, it is necessaryto interpose oil between the contact portions. Further, in the toroidalCVT, it is necessary to press the metal components (disk or roller) withan extremely strong pressure. Accordingly, the pressure of the oilinterposed therebetween must also be correspondingly high. Thus, in thecase where the toroidal CVT is applied to an automobile, the oilpressure would be increased, for example, by using the power of theengine, which, in turn, reduces, “fuel economy”.

[0012] Furthermore, when a conventional CVToperates in “reverse” thespeed cannot be shifted. It is desired to develop a continuouslyvariable transmission capable of continuously shifting in any rotationaldirection i.e. (forward/reverse) from an idling state (neutral).

[0013] Accordingly, the inventor of the present invention examinedrecent toroidal CVTs from various viewpoints to evaluate approaches tosolving the above-described problems with continuously variabletransmissions. The inventor discovered that when a conventional toroidalCVT is used in an automobile fuel consumption increases because themetal components are in “pinpoint” contact with each other. Thus,leading to the present invention.

[0014] That is to say, an object of the present invention is to improvemechanical CVTs by arranging the metal components of the transmission sothat the components come into “line contact” with each other rather thanthe conventional “pinpoint contact”. As a result of the line contactbetween the components, another object of the present invention is toreduce the pressure exerted between the respective metal components. Thereduction in pressure between the components results in a reduction inthe extra energy needed to maintain the operation thereof. By reducingthe pressure between the metal components, the fuel consumption ofautomobiles using a mechanical CVT can be reduced.

DISCLOSURE OF THE INVENTION

[0015] In order to achieve the above-mentioned objects of the invention,the means adopted in the invention according to claim 1 is described asfollows, with the reference numerals and symbols used in the descriptionof the best mode for carrying out the invention, which will be describedlater:

[0016] “A mechanical continuously variable transmission 100, capable offorward and reverse rotation, including a power roller 20 that isrotated by a rotation axle 22 connected to the input axle 11 side and aplurality of counter rollers 30, which are connected to an output axle12 and are driven to rotate by the rotation of the power roller 20coming into contact with the same, characterized in that:

[0017] the configuration of a roll surface 21 of the power roller 20 isformed into a partial configuration of a sphere, and a concave rollsurface 31 corresponding to the partial configuration of the sphere isformed on the surface of each counter roller 30, the plurality ofcounter rollers 30 are assembled rotatably into the same periphery of adisk 40, which is connected to the output axle 12, so that each of theconcave roll surfaces 31 neighboring each other roughly continues into atoric shape, and the rotation axle 22 of the power roller 20 is adaptedso as to be continuously inclined with respect to the disk 40′.

[0018] That is to say, the mechanical continuously variable transmission100 of the present invention is, for example, as shown in FIGS. 1 and 2,arranged so that the roll surface 21 of the power roller 20, which isrotated by the turning force from the input axle 11, comes into “linecontact” with each roll surface 31 of the plurality of counter rollers30 assembled into the disk 40 in a toric shape. Therefore, in themechanical continuously variable transmission 100 of the presentinvention the configuration of the roll surface 21 of the power roller20 rotated by the input axle 11 is formed into roughly the sameconfiguration as that of a surface that would be formed, for example, ifa “sphere” were cut along two planes parallel to each other. On theother hand, the configuration of the roll surface 31 of each counterroller 30 is, as shown in FIG. 3, formed into a concave shapecorresponding to the configuration of the roll surface 21 of the powerroller 20. That is, the roll surface 31 of each counter roller 30appears as a perfect “circular arc” if the same were cut off along thecenter axis of the counter roller.

[0019] Accordingly, the line of the roll surface 31 of each counterroller 30, which appears if the same were cut off at the center of therotation axle 32, forms a substantially perfect “circle” wherein theplurality of counter rollers 30 are placed adjacent to each other andare disposed in a toric shape. Within this circle, the roll surface 21of one or more power rollers 20 in a neutral position comes into linecontact with the circular arc. When the power roller 20 is inclined, theroll surface 21 remains in line contact with the circular arc portionsof the circle. Needless to say, since each of the counter rollers 30 isrotatably assembled into the disk 40 with the rotation axle 32, the samecomes into “rolling contact” with respect to the power roller 20 on thedrive side.

[0020] Here, comparing a first circle, which is formed by the rollsurface 21 of the power roller 20, and a second circle, which is formedby the roll surfaces 31 constituting the torus by continuing theplurality of counter rollers 30, the relationship of the diameters ofthe first and second circles is as described below.

[0021] First, as shown in FIGS. 1 and 2, the roll surface 21 of thepower roller 20 has, as shown in FIG. 3, a maximum portion including acircle C_(O) which goes through the center O of the sphere and a minimumportion including a circle having a diameter smaller than that of thecircle C_(O). The maximum portion of the circle formed by the rollsurface 21 of the power roller 20 may not always be the circle C_(O)shown in FIG. 3; also, the minimum circle may have a radius of 0 (zero).

[0022] Also, since the power roller 20 fits within the torus formed bythe counter rollers 30, for example, as shown in FIG. 10(A), the powerroller must have some anti through-pass measures. Accordingly, the innerdiameter of the torus of the counter rollers 30 has to be smaller thanthe outer diameter of the power roller 20. This is the case whether onlyone power roller 20 is used or a plurality of power rollers 20 are used.

[0023] The power roller 20 of the mechanical continuously variabletransmission 100 has to incline the axial direction of the rotation axle22 thereof with respect to the plane formed by the disk 40 whilemaintaining the roll surface 21 thereof in contact with each counterroller 30. In order to achieve this, a gearshift lever or handle 13 isconnected to the rotation axle 22, and the rotation axle 22 and theinput axle 11 are connected with each other using a bevel gear set orthe like adopted in the best mode, which will be described later.Needless to say, since it is necessary to maintain the state of contactbetween the roll surface 21 of the power roller 20 and the roll surface31 of the counter rollers 30, in addition to the positions of the powerroller 20, the disk 40 and the like being maintained by the casing 10,for example, leaf springs 50 shown in FIG. 4 (B) are used.

[0024] On the other hand, as for each counter roller 30, it is notabsolutely necessary to change the direction of the rotation axle 32.However, at the same position of each roll surface 31 with respect tothe disk 40, it is necessary to form a contact surface of toric shape towhich the roll surface 21 of the power roller 20 having a circular arcshape comes into contact smoothly. As for each counter roller 30, sincethe roll surface 31 thereof forms only a partial circle, a plurality ofcounter rollers 30 has to be assembled into the disk 40 so as to rotatefreely as shown in FIGS. 1 and 2. When the counter rollers 30 arecompletely assembled into the disk 40 as shown in FIG. 1, a toricsurface is formed around the inner center by the contiguous roll surface31 of each of the plural counter rollers 30.

[0025] By combining the power roller 20 and the plurality of counterrollers 30, the rotation from the input axle 11 can be transmitted tothe output axle 12 provided to the disk 40 while shifting the speed asdescribed below.

[0026]FIG. 5 shows, the transmission in “neutral”. As shown in FIG.5(B), the roll surface 21 of the power roller 20 is positioned at thesame position as the toric surface formed by the counter rollers 30, theroll surface 21 of the power roller 20 comes into contact with threecounter rollers 30 at the upper and lower surfaces respectively shown inFIG. 5(A). When the transmission is in neutral, the central counterroller 30 has the same center as the centerline, which is perpendicularto the rotation axle 22 of the power roller 20. Referring to the upperexample in FIG. 5(A), the right and left counter rollers 30 arepositioned at line symmetrical positions with respect to the centerlineof the power roller 20.

[0027] When the power roller 20 is rotated in the direction indicated bythe arrow in FIG. 5, each counter roller 30, which is brought intocontact therewith, rotates, since it is rotatably supported by the disk40 and brought into rolling contact with the power roller 20. A keypoint here is that the power roller 20 and each counter roller 30 arealways in that state of “line contact”. The reason of this is that theroll surface 21 of the power roller 20 is formed into the sameconfiguration as a portion of the surface of a sphere and the rollsurface 31 of concave shape corresponding thereto is formed on thecounter rollers 30.

[0028] As shown in FIG. 5(A), the single rotating power roller 20 comesinto contact with three counter rollers 30 respectively at the upper andlower points in FIG. 5(A), and rotates the counter rollers. Accordingly,in this case (specifically, in the case where the rotation axle 22 ofthe power roller 20 is perpendicular to the plane formed by the disk40), since any force to rotate the disk 40 is not applied thereto, thedisk 40, and accordingly the output axle 12 are not rotated.

[0029] In the case where the turning force from the input axle 11 istransmitted to the output axle 12 while being shifted, it is assumedthat the rotation axle 22 of the power roller 20 is inclined leftwardinto a state shown in FIG. 6(B); i.e., up to 30° with respect to theplane formed by the disk 40. When the rotation axle 22, i.e., powerroller 20 is inclined, the roll surface 21 moves sequentially from thecounter rollers 30 with which the same has been in contact, to anotherneighboring counter roller 30 while maintaining the contact therewith.The reason of this is that the roll surface 21 of the power roller 20 isa part of a sphere; the roll surface 31 of the counter rollers 30 has aconcave surface corresponding to the spherical surface of the rollsurface 21; each counter roller 30 is assembled into the disk 40 into atoric shape; and each roll surface 31 roughly continues each otherconsecutively. While the power roller 20 is being inclined up to 30°with respect to the disk 40, the mechanical continuously variabletransmission 100 shifts the speed continuously; the operation thereofwill be described based on the state where the same is inclined up to30°.

[0030] When the power roller 20, which is rotated by the input axle 11,is inclined up to the position of 30° with respect to the disk 40 asshown in FIG. 6(B), since the roll surface 21 of the power roller 20 isin line contact with the roll surface 31 of the counter rollers 30, thesame acts to move the counter rollers 30 in the directions indicated bythe small arrows shown in FIG. 6(A). That is to say, considering onecounter roller 30, which is in contact with the power roller 20, wherethe roll surface 21 of the power roller 20 is inclined up to 30°, arolling friction is applied to the roll surface 31 of the counter roller30. A part of the rolling friction is used as a turning force of thecounter roller 30 around the rotation axle 32 as the center; and therest thereof is used as a turning force in the direction indicated by asmall arrow shown in FIG. 6(A).

[0031] When a force in the direction indicated with dotted arrow isapplied to each counter roller 30 to which the power roller 20 comesinto contact, as a result, the disk 40 is rotated. In the case of the30° inclination, with respect to the number of revolutions of the powerroller 20, the number of revolutions of the disk 40 results in halfthereof. As a result, the output axle 12, which is connected to the disk40, is rotated at a shifted speed. Needles to say, the speed shift up tothe 30° inclination is sequentially and continuously performed.

[0032] When the inclination of the power roller 20 is increased up to90° as shown in FIG. 7(B), the entire turning force of the power roller20 is used as the turning force to rotate the counter rollers 30 in thedirection indicated with an arrow outside the figure in FIG. 7(A), andeach counter roller 30 does not rotate with respect to the disk 40. Thatis, the number of revolutions of the power roller 20 becomes equal tothe number of revolutions of the disk 40. Accordingly, in the case of90° inclination, the speed is not shifted.

[0033] Needless to say, also during the period from the above-described30° inclination to 90° inclination, the amount of rotation centeredaround the rotation axle 32 of the counter roller 30 becomes smallersequentially; and the amount of rotation of the disk 40 becomes largersequentially. As a result, the speed shift by the mechanicalcontinuously variable transmission 100 is sequentially and continuouslyperformed in accordance with the inclination amount of the power roller20, resulting in a “continuous speed shift”.

[0034] The key point in the present invention is the following fact;that is, as shown in FIG. 8, when the power roller 20 is inclined towardthe opposite side of the inclination shown in FIG. 6(B), speed shiftwith additional “reverse rotation” is performed. That is, the mechanicalcontinuously variable transmission 100 according to the presentinvention is capable of continuously performing speed shift from thestate of idling (neutral) to any rotation direction (forward/reverse).

[0035] In the above description, it is assumed that the power roller 20and the counter rollers 30 are both made of metal. However, the powerroller 20 and the counter rollers 30 may also be implemented by formingat least the roll surfaces 21 and 31 thereof from synthetic resins orceramics. Accordingly, the mechanical continuously variable transmissionaccording to claim 1 is capable of performing continuous shift whilemaking line contact between the power roller 20 and the counter rollers30. Since line contact is made, it is possible to minimize thedeformation of the roll surfaces 21 and 31 based on the Helz contact.Even when the power roller 20 and the counter rollers 30 are both madeof metal material, the amount of heat generated can be reduced, and itis possible to perform the speed shift continuously from the neutral toany rotation direction (forward/reverse).

[0036] Next, the mechanical continuously variable transmission accordingto claim 2 is the above-described mechanical continuously variabletransmission according to claim 1 in which “only one power roller 20 isprovided, and the spherical diameter of the roll surface 21 of the powerroller 20 is formed larger than the diameter of a torus formed inside bythe counter rollers 30 so that the power roller 20 is pressed toward thedisk 40 side”.

[0037] That is, in the mechanical continuously variable transmissionaccording to claim 2, as shown in FIGS. 9(B), 10 and 11, the only onepower roller 20 is formed so that the maximum diameter portion of theroll surface 21 thereof (in other words, the diameter of the sphereforming the roll surface 21) is larger than the diameter of the innertorus formed by the counter rollers 30, and that, for example, when thepower roller 20 is pressed toward the disk 40 into which the counterrollers 30 are assembled as shown in FIG. 9(B), to prevent the same frompassing through toward the opposite side of the disk 40. Owing to thisarrangement, the power roller 20 can be pressed toward the disk 40, andnot only the line contact between the power roller 20 and each counterroller 30 is reliably performed but also the power roller 20 can beinclined in the state of being pressed. The example in FIG. 9(A) is thesame as the example shown in the above-described FIG. 7(B), and is shownfor the purpose of comparison with the example shown in FIG. 9(B).

[0038] The mechanical continuously variable transmission 100 shown inFIGS. 10(A) and 11(A) correspond to the “half-toroidal” type shown inFIG. 34, in which the center of the sphere defining the configuration ofthe roll surface 21 does not exist within the power roller 20. On theother hand, the mechanical continuously variable transmission 100 shownin FIGS. 10(B) and 11(B) apparently has two power rollers 20, but theyserve as substantially a single power roller and the center of thesphere is included within these power rollers 20. Also, various methodsto press the power rollers 20 toward the disk 40 may be adopted.Particular examples of the methods to press the power rollers 20 to thedisk 40 will be described with respect to the mechanical continuouslyvariable transmission 100 according to claim 6 or 7, which will bedescribed later.

[0039] Accordingly, the mechanical continuously variable transmissionaccording to claim 2 performs not only the same functions as thataccording to claim 1, but also, since it is arranged so that the singlepower roller 20 is pressed against the disk 40, the speed shift can beperformed reliably and the size and number of components of thetransmission can be reduced.

[0040] The mechanical continuously variable transmission according toclaim 3 is the above-described mechanical continuously variabletransmission according to claim 1 or 2 in which “a pair of the disks 40attached with the counter rollers 30 respectively are assembled so as tobe parallel to each other, and one power roller 20 is disposed betweenthe pair of the disks 40, 40 so as to press the disks 40, 40 toward eachother”.

[0041] Thus, the mechanical continuously variable transmission accordingto claim 3, as shown in FIG. 11, two disks 40 to which a plurality ofcounter rollers 30 are attached respectively into a toric shape areassembled on both sides of a single or substantially single power roller20 so as to be parallel to each other.

[0042] When two disks 40 are provided and by sandwiching the powerroller 20 therewith, assembly of these components can be made easily,and, for example, by applying force to the two disks 40, the pressure onthe power roller 20 can be achieved. Accordingly, the power roller 20and the disk 40 do not have to be supported by the casing 10 for thepurpose of pressing the same.

[0043] In the above examples, there is only one power roller 20 fortransmitting the turning force from the input axle 11. However, aplurality of power rollers 20 may be used, as shown in the mechanicalcontinuously variable transmission according to claim 4. That is, themechanical continuously variable transmission according to claim 4 isthe above-described mechanical continuously variable transmissionaccording to claim 1 in which “a plurality of power rollers 20 havingthe same configuration are prepared, and these power rollers 20-20 arearranged so as to be rotated simultaneously in the same direction by theturning force from the input axle 11 side”.

[0044] Taking examples in which two power rollers are used as theplurality of power rollers, examples shown in FIGS. 12-15 areconceivable. The example shown in FIG. 12 is arranged so that one powerroller 20 shown in FIG. 1 is divided into two, and they are integratedwith a separate casing or the like so as to allow the same to rotatesimultaneously in the same direction. The mechanical continuouslyvariable transmission 100 shown in FIG. 13 is arranged so that two powerrollers 20 come into contact with the counter rollers at an angle fromthe inside thereof. As shown in FIG. 14, the power rollers come intocontact with the counter rollers from the right beside thereof. Themechanical continuously variable transmission 100 shown in FIG. 15 isarranged so that two power rollers 20 come into contact with the counterrollers at the outer surface thereof respectively.

[0045] In the mechanical continuously variable transmission according toclaim 4, since the power roller 20 is divided into a plurality ofportions, it is possible to obtain a space for assembling variouscomponents inside the disk 40 or adjacent thereto. Furthermore, there issuch merit that the contact direction of each power roller 20 withrespect to the counter rollers 30 can be altered variously. Thus, theabove facilitates assembly of the entire of mechanical continuouslyvariable transmission 100 in manufacturing.

[0046] When the power roller 20 is divided into a plurality of portionsas described above, it is made possible to allow the power rollers 20 tocome in contact with the counter rollers from any direction of the disk40 within the small casing 10. In such cases, it is necessary to alterthe direction of each counter roller 30 exposed from the disk 40. Thisis achieved by the mechanical continuously variable transmissionaccording to claim 5, and the adopted measures thereof are theabove-described mechanical continuously variable transmission accordingto claim 4 in which “it is arranged so that the direction of each of thecounter rollers 30 exposed from the disk 40 is changed and thereby thecontact point of each power roller 20 with respect to each of thecounter rollers 30 can be arbitrarily changed”.

[0047] Accordingly, the mechanical continuously variable transmissionaccording to claim 5 is arranged so that the contact points of the powerrollers 20, which are divided into a plurality of portions, can bearbitrarily determined.

[0048] As described above, it is necessary to arrange so that the powerroller 20 and the disk 40 which is assembled with the a plurality ofcounter rollers 30 press each other, and thereby the roll surfaces 21 ofthe power roller 20 always come into line contact with the roll surface31 of each counter roller 30. As the measures for the above, thepressure force may be generated by a fluid-pressure or the same may begenerated by a mechanical structure using a cam. In the best mode, whichwill be described later, it may be arranged like the mechanicalcontinuously variable transmission according to claim 6 or 7.

[0049] That is to say, the mechanical continuously variable transmissionaccording to claim 6 is the above-described mechanical continuouslyvariable transmission according to any of claims 1-5 in which “it isarranged so that the pressure between each of the counter rollers 30 andthe power roller 20 is made by leaf springs 50 interposed between asupport axle 31 of each counter roller 30 and the disk 40 supporting thesame”.

[0050] For example, in the case of the mechanical continuously variabletransmission 100 shown in FIG. 1, one power roller 20 is disposed at thecenter of the torus formed by the plurality of counter rollers 30.Therefore, when each of the counter rollers 30 positioned around thepower roller 20 is biased toward the power roller 20, the pressure ofthe power roller 20 against the disk 40 can be achieved. Since each ofthe counter rollers 30 is supported by the rotation axle 32 thereofwithin the disk 40, the same is biased toward the power roller 20 if aleaf spring 50 is provided between the disk 40 and each rotation axle 32as shown in FIG. 4.

[0051] As for the leaf spring 50, a bellville spring shown in FIG. 4(B)or a conical spring having wave-like shape may be used. In any case, theleaf spring 50 generates a biasing force in the direction of thicknessof the leaf, and the same can be included within an extremely narrowspace and generally several leaf springs, nested together, are used .

[0052] That is, since little free space is provided between each counterroller 30 and the disk 40, , a “leaf spring” is the most effectivespring for providing the biasing force. From the beginning, the powerroller 20 and each of the counter rollers 30 are designed in a statethat both are in close contact with each other. Accordingly, the spacefor pressuring them may be small. Under such conditions as describedabove, to arrange so that the disk 40 is pressed against the powerroller 20, the leaf springs 50 are the most effective.

[0053] Another alternative pressuring method is that shown in FIGS.16-25 depicting the first embodiment of the invention and is covered byclaim 7.

[0054] That is, the measures adopted by the mechanical continuouslyvariable transmission according to claim 7 are the above-describedmechanical continuously variable transmission according to any of claims1-5 in which “it is arranged so that the pressure between each of thecounter rollers 30 and the power roller 20 is made by leaf springs 50interposed between the disk 40 and a casing 10 supporting the same”.

[0055] In the mechanical continuously variable transmission according toclaim 7, shown in FIG. 16, the power roller 20, connected to the inputaxle 11, is completely assembled with the casing 10. That is, the powerroller 20 is assembled so that the center of the sphere defining theroll surface 21 of the power roller 20 is immobile. When each of thecounter rollers 30 is pressed against the power roller 20 as describedabove, close contact between the power roller 20 and the counter roller30 can be obtained satisfactorily. Accordingly, it is sufficient thatthe counter roller 30 side, i.e., the disk 40 supporting the same isarranged to be biased toward the power roller 20.

[0056] In the example shown in FIG. 16, although the output axle 12 isrotatable with respect to the casing 10, it is arranged using a bearingso that the same does not move in the right/left direction in the figureto prevent the same from being pulled off. In the inner end of theoutput axle 12, splines are formed, and an arm of the disk 40 is meshedtherewith. That is, the disk 40 is assembled so as to be movable in theaxial direction of the output axle 12 with respect to the inner endthereof, but immobile with respect to the output axle 12.

[0057] In the mechanical continuously variable transmission 100 shown inFIG. 16, a plurality of leaf springs 50 are assembled between the innerend of the inner ring of the bearing incorporated within the casing 10and the outer end of the arm of the disk 40. These leaf springs 50 arewarped in the right/left direction in FIG. 16; thereby the disk 40 isbiased just a little toward the power roller 20.

[0058] Accordingly, the mechanical continuously variable transmissionaccording to claim 7 is capable of biasing the disk 40 assembled with aplurality of counter rollers 30 against the power roller 20 of whichposition is fixed by means of a quite small component such as a leafspring 50. Thus, the line contact between the power roller 20 and eachcounter roller 30 can be stably maintained.

[0059] In the mechanical continuously variable transmission 100 shown inFIG. 16, splines are formed in the inner end of the output axle 12, andthe arm of the disk 40 is meshed therewith. That is to say, when a meansthat moves the arm in the direction opposite to the biasing direction ofthe leaf springs 50 is provided, it is possible to release the contactbetween the power roller 20 and each of the counter roller 30 toeliminate torque transmission; i.e., a “clutch operation” is achieved.It is the mechanical continuously variable transmission 100 according toclaim 8, which is arranged so as to achieve the clutch operation.

[0060] That is, the means adopted in the invention according to claim 8is the above-described mechanical continuously variable transmissionaccording to any of claims 1-7 in which

[0061] “either the power roller 20 or each of the counter rollers 30 isadapted so as to be movable in the opposite direction of the pressure toprovide such clutch function that either the power roller 20 or each ofthe counter rollers 30 is moved toward the opposite direction of thepressure and that thereby the friction contact between the power roller20 and each of the counter rollers 30 is released to eliminate thetransmission of the force therebetween”.

BRIEF DESCRIPTION OF THE DRAWINGS

[0062]FIG. 1 is a partial cutaway view of the front elevation showing anexample of a relationship between a power roller 20 and a plurality ofcounter rollers 30 in a mechanical continuously variable transmission100 according to the present invention;

[0063]FIG. 2 is a longitudinal section thereof;

[0064]FIG. 3 is a sectional view showing the shape of the end face ofthe roll surface 21 of the power roller 20 and the roll surface 31 ofthe counter roller 30 centered on a sphere O; and

[0065]FIG. 4 is an enlarged view (A) of a portion marked with line 1-1in FIG. 1, and an enlarged sectional view (B) of a leaf spring 50 usedtherein.

[0066]FIGS. 5-8 are a transverse sectional plan view (A) and alongitudinal front elevation (B), showing a power roller 20 and itsrelation to a disk 40, respectively;

[0067]FIG. 5 shows the case where the power roller 20 is positionedperpendicular to the disk 40;

[0068]FIG. 6 shows the case where the power roller 20 is inclined at anangle of 30°;

[0069]FIG. 7 shows the case where the power roller 20 is inclined at anangle of 90°; and

[0070]FIG. 8 shows the case where the power roller 20 is inclined at anangle of −30°, respectively.

[0071]FIG. 9 shows an example in which one power roller 20 is used; (A)is a schematic view showing the case where the largest portion of thepower roller 20 come into contact with each counter roller 30, and (B)is a schematic view showing the case where portions smaller than thelargest portion of the power roller 20 come into contact with eachcounter roller 30.

[0072]FIG. 10 shows an example in which portions smaller than thelargest portion of the power roller 20 come into contact with eachcounter roller 30; (A) is a schematic view showing the case where onepower roller 20 is used, and (B) is a schematic view showing the casewhere two power rollers 20, which serve as substantially one roller, areused.

[0073]FIG. 11 shows the case where two disks 40, which are parallel witheach other, are disposed on both sides of the power roller 20; (A) is aschematic view showing the case where one power roller 20 is used, and(B) is a schematic view showing the case where two power rollers 20 areused.

[0074]FIGS. 12-15 show examples of cases in which a plurality of powerrollers 20 are used and are inclined in the order of (A)-(C),respectively;

[0075]FIG. 12 shows an example in which each power roller 20 is broughtinto contact with a torus formed with the counter rollers 30;

[0076]FIG. 13 shows an example in which each power roller 20 is broughtinto contact at an angle with the inner side of the torus;

[0077]FIG. 14 shows an example in which each power roller 20 is broughtinto contact with a position where it is perpendicular to the disk 40;and

[0078]FIG. 15 shows an example in which each power roller 20 is broughtinto contact with counter rollers 30 from both upper/lower sidesthereof.

[0079]FIGS. 16-21 show a mechanical continuously variable transmission100 according to a first embodiment of the present invention,respectively;

[0080]FIG. 16 is a transverse sectional plan view of the mechanicalcontinuously variable transmission 100;

[0081]FIG. 17 is a front elevation of a disk 40 assembled with counterrollers 30;

[0082]FIG. 18 is a longitudinal section side view of the disk 40;

[0083]FIG. 19 is a partial transverse cross section showing aninterconnection relationship between an input axle 11 and one powerroller 20;

[0084]FIG. 20 is a partial longitudinal section taken along the line 2-2in FIG. 19 showing the interconnection relationship between the inputaxle 11 and the power roller 20; and

[0085]FIG. 21 is a transverse cross section taken along the line 2-3 inFIG. 19 showing the inclination mechanism of the power roller 20 withrespect to the input axle 11.

[0086]FIGS. 22-25 show one power roller 20 and its relation to the disk40; (A) is a transverse sectional plan view thereof; and (B) is alongitudinal front elevation thereof, respectively;

[0087]FIG. 22 shows the case where the power roller 20 is positionedperpendicular to the disk 40;

[0088]FIG. 23 shows the case where the power roller 20 is inclined at anangle of 30°;

[0089]FIG. 24 shows the case where the power roller 20 is positionedparallel to the disk 40; and

[0090]FIG. 25 shows the case where the power roller 20 is inclined at anangle of −15°.

[0091]FIGS. 26-28 show a mechanical continuously variable transmission100 according to a second embodiment of the present invention;

[0092]FIG. 26 is a longitudinal front elevation of the mechanicalcontinuously variable transmission 100;

[0093]FIG. 27 is a longitudinal front elevation of the mechanicalcontinuously variable transmission 100 viewed on a plane orthogonal withrespect to the case in FIG. 26, and

[0094]FIG. 28 is a plan view taken along the line 4-4 in FIG. 26.

[0095]FIG. 29 shows the power roller 20 and its relation to the disk 40of the mechanical continuously variable transmission 100 according tothe above second embodiment; (A) shows the case where the power roller20 is positioned perpendicular to the disk 40; (B) shows the case wherethe power roller 20 is inclined at an angle of −30°; and (C) shows thecase where the power roller 20 is inclined at an angle of 30°.

[0096]FIG. 30 shows the power roller 20 and its relation to the disk 40of the mechanical continuously variable transmission 100 according tothe above second embodiment; (A) shows the case where the power roller20 is inclined at an angle of 60°; and (B) shows the case where thepower roller 20 is inclined at an angle of 90°.

[0097]FIG. 31 is a graph showing the gear ratio obtained when the powerroller 20 is inclined at an angle of the direction of the vertical axle.

[0098]FIG. 32 is a drawing used in Hunt patent;

[0099]FIG. 33 is a sectional view showing a full-toroidal CVT;

[0100]FIG. 34 is a sectional view of a half-toroidal CVT; and

[0101]FIG. 35 is a perspective view showing the point contact in aconventional toroidal CVT.

DESCRIPTION OF REFERENCE NUMERALS

[0102]100 . . . mechanical continuously variable transmission, 10 . . .casing, 11 . . . input axle, 12 . . . output axle, 13 . . . gearshiftlever or handle, 14 . . . bearing, 15 . . . inclination axle, 16 . . .sleeve, 20 . . . power roller, 21 . . . roll surface, 22 . . . rotationaxle, 23 . . . opening, 30 . . . counter roller, 31 . . . roll surface,32 . . . rotation axle, 33 . . . bearing, 34 . . . base, 40 . . . disk,50 . . . leaf spring, 60 . . . turning force transmission mechanism, 61. . . intermediate axle, 62 . . . free bevel gear, 63 . . . fixed bevelgear, 84 . . . center axle, 70 . . . inclination mechanism, 71 . . .base, 72 . . . bearing, 73 . . . turning axle, 74 . . . worm, 75 . . .worm wheel.

BEST MODE FOR CARRYING OUT THE INVENTION

[0103] The inventions described above, will be described in connectionwith a mechanical continuously variable transmission 100, which is abest mode for carrying out the invention shown in the drawings. FIGS.16-25 show a first embodiment of the mechanical continuously variabletransmission 100, respectively, according to the present invention.Also, FIGS. 26-31 show a second embodiment of the mechanicalcontinuously variable transmission 100 respectively. Since eachinvention is included in the mechanical continuously variabletransmission 100, which is the best mode for carrying out the invention,the best mode of the mechanical continuously variable transmission 100will be described below in a first embodiment and a second embodimentseparately.

[0104] (First Embodiment)

[0105]FIG. 16 is a transverse sectional view showing a mechanicalcontinuously variable transmission 100 according to the presentinvention. The mechanical continuously variable transmission 100 isarranged to transmit the turning force received by an input axle 11,which protrudes rightward from a casing 10 shown in FIG. 16, to anoutput axle 12, which protrudes leftward from the casing 10 shown inFIG. 16 while shifting in a continuously variable manner. Most componentmembers thereof are incorporated into one casing 10. The mechanicalcontinuously variable transmission 100 according to the first embodimentis a type in which one power roller 20 is fitted into a torus formed bya plurality of counter rollers 30 incorporated in the disk 40, which isequivalent to the above-described mechanical continuously variabletransmission 100 shown in FIGS. 1 and 2.

[0106] As shown in FIG. 16, with respect to the casing 10, asemispherical power roller 20 is assembled so as to be rotated around arotation axle 22 thereof and to be inclined around a turning axle 73which will be described later. The rotation of the power roller 20 bythe turning force from the input axle 11 is made by a turning forcetransmission mechanism 60 shown in FIG. 16; the inclination movement ofthe rotation axle 22 is made by an inclination mechanism 70 thattransmits the operation of a gearshift lever or handle 13.

[0107] Of course, a roll surface 21 of the power roller 20 has the sameshape as that of the partial surface of a sphere. The larger diameterside of the power roller 20 is largely opened so that, as shown in FIG.16, parts of the turning force transmission mechanism 60 and theinclination mechanism 70 can be incorporated therein. Also, a cavity isformed within the power roller 20 and a base 71 constituting theinclination mechanism 70 is incorporated therein.

[0108] As shown in FIGS. 19 and 20, the turning force transmissionmechanism 60 for rotating the power roller 20 comprises an intermediateaxle 61 to which the turning force from the input axle 11 is transmittedthrough a depicted bevel gear, a free bevel gear 62 that transmits theturning force from the intermediate axle 61 to a fixed bevel gear 63 onthe power roller 20 side avoiding the turning axle 73 on the inclinationmechanism side, and a center axle 64 that fixedly connects the fixedbevel gear 63 with the power roller 20. Of course, the intermediate axle61 is provided with a bevel gear that meshes with a bevel gear fixed onthe input axle 11 side and a bevel gear that meshes with the free bevelgear 62, respectively, at both ends thereof, and in order to avoidinterfering the movement of the disk 40 and the turning axle 73, asshown in FIG. 16, inclined at a predetermined angle with respect to theaxial direction of the input axle 11 as shown in FIG. 16.

[0109] According to the above-described turning force transmissionmechanism 60, as shown in FIGS. 16-21, first of all, the turning forcefrom the input axle 11 is transmitted to the intermediate axle 61through the bevel gears and the rotation of the intermediate axle 61 istransmitted to the free bevel gear 62 through the bevel gear. The keypoint here is that it is arranged so that the turning axle 73 forperforming the inclination movement of the power roller 20 is located atthe center thereof so as to allow the free bevel gear 62 to turn freelyaround the turning axle 73. Owing to this arrangement, irrespective ofthe inclination movement of the power roller 20 by the operation of thegearshift lever or handle 13 which will be described later, the turningforce of the input axle 11 side can be transmitted to the fixed bevelgear 63 on the power roller 20 side.

[0110] To the free bevel gear 62 which is freely rotatable on theturning axle 73, the center axle 64 is connected via the fixed bevelgear 63, and these center axle 64 and free bevel gear 62 are adapted soas to rotate freely with respect to the base 71 on the inclinationmechanism 70 side through a bearing 72.

[0111] As a result, as shown in FIG. 19, the power roller 20 is rotatedby the turning force from the input axle 11 being completely independentfrom the inclination operation by the inclination mechanism 70 whichwill be described later. Even when the power roller 20 is inclined to aposition as shown in FIGS. 22-25, the power roller 20 is stably drivento rotate by the input axle 11.

[0112] Next, the inclination mechanism 70 for performing the inclinationmovement operation of the power roller 20 will be described. Theinclination mechanism 70 comprises, as shown in FIGS. 16-21, the base 71that is received within the power roller 20 via the bearing 72, theturning axle 73 which is bridged on the base 71 as shown in FIGS. 19 and21 and goes through the center of the free bevel gear 62 constitutingthe above-described turning force transmission mechanism 60, a worm 74fixedly attached to one end of the turning axle 73, and a worm wheel 75which meshes with the worm 74 and is provided at the inner side end ofthe gearshift lever or handle 13 that protrudes out of the casing 10 asshown in FIG. 20.

[0113] According to the above-described inclination mechanism 70, asshown in FIG. 20, the worm 74 is rotated by turning adjustment of thegearshift lever or handle 13, and is meshed with the worm wheel 75,which is in turn rotated corresponding to the amount and direction ofthe rotation of the worm 74. The key point here is that the worm 74 isprovided on the gearshift lever or handle 13 side and the worm wheel 75is provided on the turning axle 73 side. The reason of this is asfollows: when the mechanical continuously variable transmission 100 isactivated, the turning axle 73 side is subjected to a reaction force.However, by arranging as described above, it is possible to prevent thegearshift lever or handle 13 side from being subjected to the reactionforce and stable turning adjustment of the gearshift lever or handle 13can be performed.

[0114] As shown in FIG. 19, because the worm wheel 75, which is turnedcorresponding to the turning adjustment of the gearshift lever or handle13, is integrated with the turning axle 73 bridged on the base 71, theinclination movement of the base 71 is made around the axis of theturning axle 73, i.e., around the turning axle 73 shown as a section inFIG. 20. Needless to say, the power roller 20, which is inclined by theinclination mechanism 70, is also driven to rotate by the turning forcetransmission mechanism 60 included in a separate system, which is quitedifferent from the inclination mechanism 70.

[0115] State of the inclination movement of the power roller 20 is shownin FIGS. 22-25 representatively. Since the mechanical continuouslyvariable transmission 100 performs continuous shift, it is needless tosay that the states shown in FIGS. 22-25 are shifted continuously. InFIGS. 22-25, (A) is a schematic plan view showing the worm wheel 75; and(B) is a longitudinal section side view showing a relationship betweenthe power roller 20 and each counter roller 30 in the respective states.

[0116] The counter rollers 30, with which the power roller 20 thatperforms the rotation and the inclination movement as described abovecomes into contact, will be described. In the mechanical continuouslyvariable transmission 100 according to the present embodiment, a numberof counter rollers 30 are adapted to be assembled into one disk 40 intoa toric shape as shown in FIGS. 16-18. The roll surface 31 of eachcounter roller 30 is formed into a concave shape so as to come into linecontact with the outer surface of a sphere as shown in FIGS. 17 and 18.Each end portion of the counter rollers 30 is supported by one disk 40so as to form a consecutive range. The support of the counter rollers 30to the disk 40 is made in such state as described in FIG. 1, that therotation axle 32 is supported by the bearing 33 so as to rotate freelywith respect to the disk 40.

[0117] The disk 40 is for integrating the reaction force received byeach counter roller 30 from the rotation of the power roller 20 and foroutputting the same to the output axle 12 side. Accordingly, the disk 40is spline-connected with the output axle 12 via a plurality of legs 41as shown in FIG. 16. The reason why the disk 40 is spline-connected tothe output axle 12 is as follows: it is arranged so that the disk 40reliably transmits the turning force to the output axle 12 side, whilethe disk 40 comes into elastic contact with the power roller 20 owing tothe biasing force from leaf springs 50 in the rightward direction inFIG. 16.

[0118] Therefore, in the mechanical continuously variable transmission100 according to the embodiment 1, a plurality of leaf springs 50 areassembled between the legs 41 of the disk 40 and the inner ring of thebearing 14 that rotatably supports the output axle 12 with respect tothe casing 10. The leaf springs 50 function so as to elastically pressthe disk 40 assembled with the number of counter rollers 30 against thepower roller 20 supported by the casing 10.

[0119] (Second Embodiment)

[0120]FIGS. 26-31 show a mechanical continuously variable transmission100 according to a second embodiment of the present invention. Thegeneral structure of the mechanical continuously variable transmission100 is similar to that shown in FIG. 11 (B). However, in the mechanicalcontinuously variable transmission 100 according to the secondembodiment, it is arranged so that the transmission of turning forcefrom the input axle 11 and the inclination movement of the power roller20 by the gearshift lever or handle 13 are made by each memberincorporated within the power roller 20 and thereby the size and numberof components of the entire transmission can be decreased.

[0121] That is, in the mechanical continuously variable transmission 100according to the second embodiment, as shown in FIGS. 26 and 27, thepower roller 20 comprises two members having the same configuration inwhich the roll surface 21 is in a partial configuration of a sphererespectively, and the two power rollers 20 are integrally connected by arotation axle 22, which serves as the center thereof. Owing to thisarrangement, the power roller 20 has such configuration that roughlyupper and lower quarters of a sphere are cut off, and in a portion whichgoes through the center of the sphere, an opening 23 shown in FIG. 27 isformed all along the periphery thereof. Within the opening 23, as shownin FIG. 26, an input axle 11 from the right in the figure is inserted;and from the left in the figure, an inclination axle 15, which isrotated by a gearshift lever or handle 13, is inserted.

[0122] Since the inner end of the input axle 11 inserted into the powerroller 20 engages the inner surface of the power roller 20 via bevelgears, the turning force of the input axle 11 causes the entire of thepower roller 20 to rotate around the rotation axle 22. That is, thepower roller 20 is rotated by the input axle 11 around the rotation axle22 shown in FIG. 26 taken as the rotational axle in the right/leftdirection in the figure. Needless to say, since the opening 23, whichallows the input axle 11 to go through, is formed in the power roller 20all along the periphery thereof as shown in FIG. 27, the power roller 20rotates without interfering with the input axle 11 or the inclinationaxle 15, which will be described later.

[0123] On the other hand, the inner end of the inclination axle 15,which is inserted within the power roller 20 from the side opposite theinput axle 11, is connected to a sleeve 16, which is fitted to the outerperiphery of the rotation axle 22 of the power roller 20. The sleeve 16is incorporated within the power roller 20 through various bearings, andis arranged so as to rotate freely with respect to the rotation axle 22on the power roller 20 side. In other words, even when the power roller20 is rotated by the input axle 11, the sleeve 16 does not rotate. As aresult, the inner end of the inclination axle 15 can be secured.

[0124] Because the inner end of the inclination axle 15 is fixedlyconnected to the sleeve 16, when the gearshift lever or handle 13 isrotated in a predetermined direction, the power roller 20 can be shiftedcontinuously into various inclination states, as shown in FIGS. 29 and30. Even after shifting, the rotation of the power roller 20 by theinput axle 11 is not prevented.

[0125] The rotation of the power roller 20 by the input axle 11 and theinclination by the gearshift lever or handle 13 of the power roller 20are described above. Since the power roller 20 comes into contact withmany counter rollers 30 disposed within the casing 10, the turning forceof the power roller 20 is shifted corresponding to the inclination statethereof, and transmitted to the disk 40, which supports the counterrollers 30. The disk 40 is connected with the output axles 12 as shown,for example, in FIG. 26. As a result, the rotation of the input axle 11is shifted and outputted from the output axles 12.

[0126] In the second embodiment, as shown in FIG. 26, a plurality ofleaf springs 50 are interposed between the casing 10 and the disk 40.Accordingly, owing to the biasing force of these leaf springs 50, thedisk 40 is always pressed toward the power roller 20 side.

[0127] Further, many counter rollers 30 assembled into the disk 40 areformed into a toric shape with the inner edge of each roll surface 31 asshown in FIG. 28. Accordingly, when the power roller 20 is inclined intoany position, the roll surface 21 of the power roller 20 and the rollsurface 31 of each counter roller 30 come into line contact with eachother as described above. Furthermore, the power roller 20 is always incontact with the roll surface of toric shape formed with each counterroller 30. Accordingly, the size of the power roller 20 with respect tothe torus of the counter rollers 30 falls in the relationship, which hasbeen illustrated in the above FIG. 11 (B) and as shown in FIG. 28.

[0128] State of the shift by the mechanical continuously variabletransmission 100 according to the second embodiment is as shown in agraph of FIG. 31. In this graph, the axis of abscissas representsinclination angle of the power roller 20; the axis of ordinatesrepresents gear ratio. The symbol minus (−) represents the rotation inthe inverse direction of the rotation direction of the input axle 11.

[0129] Industrial Applicability

[0130] As described above in detail, it is possible to allow the rollsurface 21 of the power roller 20 and the roll surfaces 31 of theplurality of counter rollers 30 to come into line contact with eachother in the mechanical continuously variable transmission 100 of thepresent invention. As a result, the turning force from the input axle 11side can be effectively transmitted to the output axle 12 side without asignificant energy loss.

[0131] Also, since the power roller 20 and each of the counter rollers30 come into line contact with each other, the power can be transmittedwithout strongly pressing the power roller 20 against the counterrollers 30. As a result, oil for suppressing heat generation does notneed to be supplied. When the oil is supplied, it is not necessary toincrease the oil pressure.

[0132] Further, by only changing the inclination angle of the powerroller 20 in the mechanical continuously variable transmission 100 ofthe present invention, it is possible to continuously shift from thestate of idling (neutral) to any of the forward/reverse rotationdirections.

[0133] Accordingly, when the mechanical continuously variabletransmission 100 of the present invention is used as the component of amachine tool or automobile, since the same permits not only continuousshift including reverse but also reduces energy loss for operating thesame to a minimum level; thus the same is extremely useful in industry.

1. A mechanical continuously variable transmission capable of forwardand reverse rotation including a power roller which is rotated by arotation axle connected to the input axle side and a plurality ofcounter rollers which are connected to an output axle and are driven torotate by the rotation of the power roller coming into contact with thesame, wherein the configuration of a roll surface of the power roller isformed into a partial configuration of a sphere, and a concave rollsurface corresponding to the partial configuration of the sphere isformed on a surface of each counter roller, the plurality of counterrollers are assembled rotatably into the same periphery of a disk, whichis connected to the output axle, so that each of the concave rollsurfaces neighboring to each other roughly continues into a toric shape,and the rotation axle of the power roller is adapted so as to becontinuously inclined with respect to the disk.
 2. The mechanicalcontinuously variable transmission according to claim 1, wherein onlyone power roller is provided, and the spherical diameter of the rollsurface of the power roller is formed larger than the diameter of atorus formed inside by the counter rollers so that the power roller ispressed toward the disk side.
 3. The mechanical continuously variabletransmission according to either claim 1 or 2, wherein a pair of thedisks attached with the counter rollers respectively are assembled so asto be parallel to each other, and one power roller is disposed betweenthe pair of the disks so as to press the disks toward each other.
 4. Themechanical continuously variable transmission according to claim 1,wherein a plurality of power rollers having the same configuration areprepared, and these power rollers are arranged so as to be rotatedsimultaneously in the same direction by the turning force from the inputaxle side.
 5. The mechanical continuously variable transmissionaccording to claim 4, wherein it is arranged so that the direction ofeach of the counter rollers exposed from the disk is changed and therebythe contact point of each power roller with respect to each of thecounter rollers can be arbitrarily changed.
 6. The mechanicalcontinuously variable transmission according to any of claims 1 to 5,wherein it is arranged so that the pressure between each of the counterrollers and the power roller is made by leaf springs interposed betweena rotation axle of each counter roller and the disk supporting the same.7. The mechanical continuously variable transmission according to any ofclaims 1 to 5, wherein it is arranged so that the pressure between eachof the counter rollers and the power roller is made by leaf springsinterposed between the disk and a casing supporting the same.
 8. Themechanical continuously variable transmission according to any of claims1 to 7, wherein either the power roller or each of the counter rollersis adapted so as to be movable in the opposite direction of the pressureto provide such clutch function that either the power roller or each ofthe counter rollers is moved toward the opposite direction of thepressure and that thereby the friction contact between the power rollerand each of the counter rollers is released to eliminate thetransmission of the force therebetween.